In power line communication, a receive end generally performs frame synchronization, channel estimation, and the like using a preamble in a system whose physical layer frame structure includes the preamble. The preamble includes several orthogonal frequency division multiplexing (OFDM) symbols.
To transmit a large amount of information, a relatively long frame length is set for a physical layer frame in the power line communication. Because a power line communication channel is time varying, when the frame length is relatively long (for example, greater than 10 milliseconds (ms)), the receive end cannot reflect the time-varying characteristic of the channel based on only a result obtained after channel estimation is performed using the preamble. Consequently, channel estimation accuracy of the receive end is relatively low, resulting in relatively low data decoding accuracy of the receive end.